﻿<p>This entity defines an action which acts on a point.
A point action is typically connected with a point connection.
It may also be connected with a curve member or curve connection,
or surface member or surface connection.</p>

<blockquote class="history">
HISTORY&nbsp; New entity in IFC2x2.
</blockquote>

<blockquote class="change-ifc2x4">
IFC4 CHANGE&nbsp; Attributes in the supertypes
<em>IfcStructuralActivity</em> and <em>IfcStructuralAction</em> changed.  Use definitions changed,
informal propositions added.</blockquote>

<p><b><u>Coordinate Systems</u></b>:</p>

<p>See definitions at <em>IfcStructuralActivity</em>.</p>

<p><b><u>Topology Use Definitions</u></b>:</p>

<p>Standard Case:<br>
If connected with a point item, instances of <em>IfcStructuralPointAction</em>
shall not have an <em>ObjectPlacement</em> nor a <em>Representation</em>.
It is implied that the placement and representation of the action is the same
as the structural item.</p>

<p>Special Case 1:<br>
If connected with a curve item or surface item, instances of <em>IfcStructuralPointAction</em>
shall have an <em>ObjectPlacement</em> and <em>Representation</em>, containing an <em>IfcVertexPoint</em>.
See <em>IfcStructuralActivity</em> for further definitions.</p>

<blockquote class="note">NOTE&nbsp; In order to model concentrated actions on a curve or surface item,
<em>IfcStructuralCurveAction</em> or <em>IfcStructuralSurfaceAction</em> of type DISCRETE is
preferable since they do not require an extra topology representation in this case.
An <em>IfcStructuralPointAction</em> should be used for a concentrated action on a curve or surface
item only when an explicit vertex point representation is actually desired.</blockquote>

<p>Special Case 2:<br>
If not connected with a structural item (which may happen in an incomplete or
conceptual model), a point action should have an <em>ObjectPlacement</em> and
<em>Representation</em>, containing an <em>IfcVertexPoint</em>.
See <em>IfcStructuralActivity</em> for further definitions.</p>